// ========================================================================
// Copyright 2008-2009 NEXCOM Systems
// ------------------------------------------------------------------------
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at 
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ========================================================================
package org.cipango.littleims.util;

import java.util.Random;

import sun.misc.BASE64Encoder;

public class Base64
{

	public static final char[] alphabet = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', // 0 to
																					// 7
			'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', // 8 to 15
			'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', // 16 to 23
			'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', // 24 to 31
			'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', // 32 to 39
			'o', 'p', 'q', 'r', 's', 't', 'u', 'v', // 40 to 47
			'w', 'x', 'y', 'z', '0', '1', '2', '3', // 48 to 55
			'4', '5', '6', '7', '8', '9', '+', '/' }; // 56 to 63

	// ////////////////////////////////////////////////////////////////////
	// ////////////////////////////////////////////////////////////////////

	public static String encode(String s)
	// ////////////////////////////////////////////////////////////////////
	{
		return encode(s.getBytes());
	}

	public static String encode(byte[] octetString)
	// ////////////////////////////////////////////////////////////////////
	{
		int bits24;
		int bits6;

		char[] out = new char[((octetString.length - 1) / 3 + 1) * 4];

		int outIndex = 0;
		int i = 0;

		while ((i + 3) <= octetString.length)
		{
			// store the octets
			bits24 = (octetString[i++] & 0xFF) << 16;
			bits24 |= (octetString[i++] & 0xFF) << 8;
			bits24 |= (octetString[i++] & 0xFF) << 0;

			bits6 = (bits24 & 0x00FC0000) >> 18;
			out[outIndex++] = alphabet[bits6];
			bits6 = (bits24 & 0x0003F000) >> 12;
			out[outIndex++] = alphabet[bits6];
			bits6 = (bits24 & 0x00000FC0) >> 6;
			out[outIndex++] = alphabet[bits6];
			bits6 = (bits24 & 0x0000003F);
			out[outIndex++] = alphabet[bits6];
		}

		if (octetString.length - i == 2)
		{
			// store the octets
			bits24 = (octetString[i] & 0xFF) << 16;
			bits24 |= (octetString[i + 1] & 0xFF) << 8;

			bits6 = (bits24 & 0x00FC0000) >> 18;
			out[outIndex++] = alphabet[bits6];
			bits6 = (bits24 & 0x0003F000) >> 12;
			out[outIndex++] = alphabet[bits6];
			bits6 = (bits24 & 0x00000FC0) >> 6;
			out[outIndex++] = alphabet[bits6];

			// padding
			out[outIndex++] = '=';
		}
		else if (octetString.length - i == 1)
		{
			// store the octets
			bits24 = (octetString[i] & 0xFF) << 16;

			bits6 = (bits24 & 0x00FC0000) >> 18;
			out[outIndex++] = alphabet[bits6];
			bits6 = (bits24 & 0x0003F000) >> 12;
			out[outIndex++] = alphabet[bits6];

			// padding
			out[outIndex++] = '=';
			out[outIndex++] = '=';
		}

		return new String(out);
	}

	// ////////////////////////////////////////////////////////////////////
	// ////////////////////////////////////////////////////////////////////

	public static void main(String[] args)
	{
		String s = Long.toString(new Random(System.currentTimeMillis()).nextLong());
		System.out.println(s);

		System.out.println((Base64.encode(s)));
		System.out.println(new BASE64Encoder().encode(s.getBytes()));

		System.out.println((Base642.encode(s)));

	}
}
